1. Field of the Invention
The present invention relates to a high-speed shear for transversely cutting rolled strip with knife carriers which are drivable for rotation and are arranged in pairs opposite each other.
2. Description of the Related Art
High-speed shears of the above-described type are generally known in the art.
For example, DE 196 37 862 A1 describes a flying shear with knife edges arranged on oppositely located drums, wherein the knife edges can be accelerated to the feeding speed of the strip to be cut and can be moved towards each other for carrying out a cut. The invention on which this shear is based resides in that the drums arranged on opposite sides can be accelerated by a driving device provided for at least one of the drums to a circumferential speed corresponding to the speed of the strip to be cut, and that at least one of the drums is provided with a separately controllable adjusting device.
DE 197 46 528 A1 describes a high-speed shear which includes two drums, wherein one of the drums is equipped or constructed as a chisel knife and the other is equipped or constructed as an anvil interacting with the other drum. The two drums are moved towards each other for cutting a continuously rolled strip by means of a controlled adjusting device. The synchronization of the two drums is effected by means of electric, electronic or gear-technological means.
EP 0 904 877 A2 discloses a high-speed shear with knife drums which have slightly different diameters and are driven with a slight speed difference through an external branched gear unit. Using an adjusting device through spreading levers, the drums are moved into the cutting position with oppositely located positions of the knives and, after the cut of the rolled strip has been carried out, the drums are moved once again apart from each other.
Finally, DE-OS 26 54 866 describes a flying shear with coupled knife drums. The shear includes a drum turning device with a force transmission coupling both drums for speeds synchronous with the running speed of the supplied material, and a drum adjusting device for adjusting a cutting drum between an open position and a cutting position, and a control device for the motor of the adjusting device, wherein the control device controls the start of the first cutting drum and the adjustment into the cutting position and the return movement of the drum into the initial position. The means for coupling the drums, the drum adjusting device as well as the control device required for the drum adjusting device are of extremely complicated construction which is susceptible to problems. When force transmission takes place, four gear wheels are in engagement with each other, so that a play of the sides of the gear teeth caused by the engagement may lead to an angular deviation of the interacting drum knife and, thus, to damage or to unclean cuts.